DODGE INTREPID ENGINE PROBLEM

2000 Dodge Intrepid • 230,000 miles

2.7 L engine - recently replaced water pump which failed and while at it I also replaced the timing chain and primary tensionser. Now, after driving for a while (20 minutes or more) the idle drops at stops to between 4-5K and occasionally stalls, but prior to this (even after engine fully warms up and reaches closed circuit) there is no problem at all. What could be the source of this?

If you disconnected the battery, the Engine Computer has to relearn "minimum throttle" before it will know when it must be in control of idle speed. You also typically won't get the nice idle flare-up to 1500 rpm at start-up. Drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.